# A107507 (b-file synthesized from sequence entry) 0 1 1 264 2 13488 3 278168 4 3237984 5 25290408 6 147204624 7 684347448 8 2666539200 9 9015945800 10 27141718896 11 74182306776 12 186879023392 13 439124493288 14 971672262864 15 2040402823544 16 4092008534400 17 7879085829000 18 14630516376112 19 26297796632856 20 45903762942432